The 'missing operating system' or 'operating system not found' error message usually appears on a black window when you start your Windows computers. This error is very common for Dell, Acer, Lenovo, HP and Sony desktops and laptops. When your Windows 10/8/7/XP/Vista operating system not found on its boot drive, it's impossible to start the computer until the operating system is restored. You can read on to get error details or directly jump to comprehensive solutions.
- Error Finding Your Systems Active Partition Daz
- Error Finding Your Systems Active Partition (read The Readme File)
- Error Finding Your Systems Active Partition Key
- Error Finding Your Systems Active Partition System
- Error Finding Your Systems Active Partition Solucion
- Set Partition Active
For a FAT32 partition, reformat the partition, or convert the partition to an NTFS file system partition by using the Convert.exe command. Note When you format a partition, all data is removed from the partition. This data includes all the files on the partition. Set active partition in Disk management is another way to make partition bootable, Server 2008, Windows 10, and other Windows Systems can share steps as follow to set active partition: 1. Press shortcut key WIN+R to open RUN box, type diskmgmt.msc, or you can just right-click on Start bottom and select Disk Management in Windows 10 and Windows.
Workable Solutions | Step-by-step Troubleshooting |
---|---|
Fix 1. Check BIOS | Press and hold 'F12/F10' to enter BIOS..Full steps |
Fix 2. Reboot from a bootable disk | Press and hold 'F10' and press 'Power'..Full steps |
Fix 3. Set BIOS to default settings | Find BIOS and enable the default setup option..Full steps |
Fix 4. Rebuild MBR using cmd | Insert the Windows installation CD/DVD..Full steps |
Fix 5. Rebuild MBR using software | Boot PC from EaseUS Partition Master ..Full steps |
Fix 6. Rebuild MBR for HP | Boor from Windows Operating System Disc..Full steps |
Fix 7. Set correct partition active | Boot from EaseUS WinPE bootable disk..Full steps |
Causes of 'Missing Operating System' or 'Operating System Not Found'
When you pressed the power button to boot a PC, in the first place, BIOS tries to find an operating system on a hard drive to boot from, later wakes your PC up. However, if the BIOS fails to detect the operating system where it should be, you will receive one of the following error messages, which tells the same problem on different operating system versions.
Error message 1.
Missing Operating System
Error message 2.
Operating system not found
For professionals, they'll soon notice that something goes wrong with the BIOS configuration, hard drive health, or the Master Boot Record. To be specific, the causes of the error are as follows.
- The basic input/output system (BIOS) does not detect the hard disk
- The hard disk drive is damaged
- Improper/incorrect BIOS settings
- Windows Master Boot Record (MBR) is corrupt/damaged
- An incompatible partition is set as active
Solutions to Operating System Not Found or Missing in Windows 10/8/7
After knowing the causes for an operating system not found or missing in Windows, now it's time to apply effective solutions to restore the missing operating system.
Solution 1. Check if the hard drive is detected by BIOS
Step 1: Press and hold 'F12/F10' while pressing the 'Power' button to turn on the PC.
Step 2: Release F12/F10 when the BIOS Setup Utility is displayed.
Step 3: Try to find IDE Primary Master, IDE Primary Slave, IDE Secondary Master and check whether they can be detected or not.
If no disk is shown or displayed as None/Not Detected, it means that the BIOS doesn't detect the drive and you may select None to Auto. This may solve OS not found error.
If the system disk information is displayed, it means that BIOS can detect the hard drive and you need exit BIOS.
Solution 2. Test hard drive problems
Step 1: Press and hold 'F10' and press the 'Power' button to turn on the PC > Release F10 after the PC screen display you with test
Step 2: Use the right arrow to select the 'Tools' menu in the BIOS Setup Utility
Step 3: Then select 'Hard Drive Self Test' > Press 'Enter' to start the test
After the test, you'll get two results:
#1. All tests passed
the hard drive is not damaged. You may jump to Solution 3 to reset BIOS to the default state.
#2. The test failed
You should contact your hard disk or computer manufacturer for a replacement as long as these devices are under warranty.
Solution 3. Set BIOS to default settings
Improper settings or incorrect BIOS setting may also cause the issue 'operating system not found' in your PC. You can try to set BIOS to default settings to solve the problem.
Step 1: Restart PC and enter BIOS.
Step 2: Find BIOS and enable the default setup option, including Load Optimal Defaults, Get Default Values, Load Optimized Defaults, Load Setup Defaults, and so on.
Step 3: Press 'F10' to save changes and quit from BIOS.
If this method doesn't work, the MBR disk could be damaged and you may jump to Solution 4 to find the MBR disk repair method.
Solution 4. Repair MBR with the installation CD/DVD
Both wrong operation and virus infection can damage MBR, which locates in the first sector - usually sector 0 of the hard disk. Thus, Windows will not boot. You can try to repair MBR using the Windows installation disk in Command Prompt.
Insert Windows Operating System Disc to the optical (CD/DVD) drive
Step 1: Press the 'Power' button to turn on the PC > Hit 'Enter' when Boot from CD prompt
Step 2: Press 'R' key in Windows Setup Menu to start the Recovery Console
Step 3: Type: FIXMBR at the C:> prompt and hit 'Enter'
Step 4: Press 'Y' key > hit 'Enter' when asked if you want to write a new MBR;
Step 5: Restart PC by pressing the 'Power' button when the MBR completes the writing process.
Solution 5. Rebuild MBR without Windows Installation CD/DVD
Error Finding Your Systems Active Partition Daz
If you prefer an easier way to rebuild or repair the MBR disk, you may apply third-party partition magic software - EaseUS Partition Master to perform an automatic repair.
Boot your Windows from the WinPE environment you created and start to repair MBR with a few clicks.
Step 1.Create a WinPE bootable disk.
- Download and launch EaseUS Partition Master on a new PC which runs the same system as yours.
- Click 'WinPE Creator' on the toolbar. And select to create the bootable disk on a USB drive. If your computer has a CD/DVD drive, you can also create the bootable disk to CD/DVD.
- Click 'Proceed' to finish the process.
Step 2.Rebuild MBR.
- Connect the bootable USB or CD/DVD to your PC.
- Press 'Del' when you are restarting the computer. Boot your computer from 'Removable Devices' or 'CD-ROM Drive'. And then EaseUS Partition Master will run automatically.
- Right-click the disk whose MBR is damaged. Choose 'Rebuild MBR' to continue.
- Select the type of MBR with the current operating system. Then, click 'OK'.
- Click the 'Execute 1 Operation' button at the top-left corner and click 'Apply' to build the MBR. After that, your computer can boot normally again.
Solution 6. Repair MBR for HP
Solution 4~5 to corrupted MBR repair is applicable to various computer/laptop brands. On top of that, some brands provide customers with inbuilt tools to deal with MBR issues. For example, the Windows Operating System Disc (OSD) provided with your HP notebook PC can be used to repair the Master Boot Record.
Follow all steps at https://support.hp.com/us-en/document/c00476274
Solution 7. Set the correct partition active
When Windows is running under Legacy BIOS + MBR mode, the boot partition/system partition should be set as active so that MBR can pass boot right to boot manager and find Windows. If the system partition or boot partition is not set to active, you may encounter the operating system not found issue.
In the same partition tool, create the EaseUS Partition Master bootable USB first, and follow the steps to set the boot partition active:
Step 1. Download and launch EaseUS partition manager software.
Step 2. On the disk map, right-click the desired partition and choose 'Set Active'. The software will automatically execute the operation and create an active partition for you.
Do You Need Specialized Services for System Boot Issues?
EaseUS also provides 1-on-1 remote assistance to fix the boot issue. If the solution above does not work for you, please contact our professionals via Email or LiveChat in this page. To ensure our professional assistance work, you are suggested to connect the unbootable system drive to a healthy computer when getting connected with us.
Conclusion
Error Finding Your Systems Active Partition (read The Readme File)
All effective solutions to the 'Missing Operating System' or 'Operating system not found' error are carefully presented on this page. You may try any one of the methods to resolve the issue and get a healthy Windows system back and continue using your computer again.
Quick Navigation:
The issue: active partition not found
An active partition is a partition on a hard drive which is set as the bootable partition and contains the operating system. Only one partition on each hard drive can be set as an active partition or bootable partition. If there is a problem with the active partition, your computer won’t boot successfully. Active partition not found is a common issue reported by a lot of users. Here is a real case:
“I keep getting ‘Active partition not found’ error. It says press any key and then shows the message again. What do I do to fix it??”
Following are possible causes for the error of “Active partition not found! Press any key…”:
- Windows installation hard drive is not detected by BIOS.
- BIOS settings are set improperly.
- System files are damaged or lost.
- Windows boot files in system partition are no longer active…
Then, how to fix the boot partition not found error efficiently?
How to fix active partition not found in Windows 10 efficiently?
According to the causes, there are four effective solutions for your reference:
Solution 1: Check if the Windows installation hard drive is detected by BIOS
1. Restart the computer and continuously press a specific key to get into BIOS. The key to open BIOS can be listed on the first screen that appears, before the Windows logo shows up. It is likely to be Esc, Del, F2, F8, F10 or F12.
2. Find Primary IDE Master, Primary IDE Slave, Secondary IDE Master, and Secondary IDE Slave, which can be listed under the Advanced tab. Keygen serial visualgdb download. Then, check if they are detected or not.
3. If they are shown as None/Not Detected, it means that the BIOS doesn’t detect the hard drive. You can select None/Not Detected to Auto and restart your computer to see if the error is fixed. If the system disk information is displayed after IDE Master/Slave, it means that the BIOS can detect the hard drive and you can try other solutions below.
Solution 2: Set BIOS to default settings
1. Restart your PC and enter BIOS as you do in Solution 1.
2. You might see a line at the bottom that says Setup Defaults — F9 on many PCs. Press this key and confirm with OK or Yes to restore the default BIOS settings.
✎Tips: On some machines, you may find the “default settings” option under the Security, Initialize, or Reset tab. Look for an option like Restore Factory Defaults or Reset All Settings.
3. Press F10 to Save and Exit. Restart your PC to see if the active partition not found error is fixed.
Error Finding Your Systems Active Partition Key
Solution 3: Repair system files via Startup Repair
1. Insert Windows 10 installation media and boot your computer from it.
2. Choose the correct time and keyboard type and click Next.
3. In the next screen, choose Repair your computer.
4. Go to Troubleshoot > Advanced options > Startup Repair. Wait for the repair process to complete.
Solution 4: Set the system partition active
1. Insert Windows 10 installation media and boot from it.
2. Navigate to Repair your computer > Troubleshoot > Advanced options > Command Prompt.
Error Finding Your Systems Active Partition System
3. In Command Prompt, type following commands and press Enter after each:
- diskpart
- list disk
- select disk 0 (replace 0 with your computer’s primary disk)
- list partition
- select partition 1 (replace 1 with the system partition’s number on your computer)
- active
- exit
4. Restart your computer to see if the problem is solved.
If all the solutions fail, you can try system restore Windows 10 from boot if you have created restore points before.
Error Finding Your Systems Active Partition Solucion
Further reading: backup Windows in case that errors occur
Apart from the active partition not found error, you may encounter other unexpected errors. System restore can be the last resort to fix your issues, so it’s necessary to backup Windows regularly. The best free backup software, AOMEI Backupper Standard, offers you all-around backup solutions:
▶ There are four types of backup available: System Backup, Disk Backup, Partition Backup, and File Backup. You can choose one type based on your needs.
▶ You can set your backup tasks to run automatically with the Schedule feature.
▶ You are allowed to do incremental and differential backups to improve the backup efficiency and save storage space.
▶ You can set your backup tasks to run automatically with the Schedule feature.
▶ You are allowed to do incremental and differential backups to improve the backup efficiency and save storage space.
All Windows PC operating systems including Windows 10/8.1/8/7/Vista/XP are supported. Just download this freeware to have a try.
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Win 10/8.1/8/7/XP
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Use two functions in AOMEI Backupper to protect your computer from now on:
1. Create bootable media to boot your computer in case of boot failure.
2. Perform system backup when the computer is in good condition.
To sum up
Set Partition Active
You can resort to the four solutions offered in this article to fix the issue of active partition not found in Windows 10. To get prepared for potential errors, you’d better backup Windows with AOMEI Backupper regularly. You can also use AOMEI Backupper as free PC clone software. Try it now to discover more!